Optical systems that perform mathematical operations other than addition are difficult to construct because of two fundamental facts. First, light intensity is a positive-definite physical quantity. While electrical voltage can be positive or negative, light intensity can only be positive or zero. Second, photons can be created and destroyed at will in optical systems. In electrical systems, electrons are conserved. The nonlinear optical effects which are most often associated with multiplication are primarily contained in the third-order dependence of the electrical susceptibility on the electrical field incident optical wave(s). (First-order gives birefringence, second-order gives photoelectrons, and third-order produces photorefractive effects.) The optical system described herein uses second-order effects to perform certain mathematical operations. One such second-order effect is the quenching effect described in U.S. Pat. No. 5,598,053 issued Jan. 28, 1997. In this patent, the quenching effect is modeled as an induced increase to the natural decay rate of the phosphor where the added increase is proportional to the intensity of the quenching illumination.
By combining the luminenscent and quenching properties of phosphors with first-order relaxation subsystems, certain mathematical operations can be performed. The optical system described will enable collective dynamic behaviors such that the relative strengths of the output light intensities (as compared to those of the input light intensities) correspond to the results that would be achieved by performing certain mathematical computations with numbers in the same relative proportions to each other (as the input and output light intensities). By measuring the light intensities, the equivalent computational answers can be obtained from the system. The potential equivalent computations include all mathematical operations describable by the physics that apply to the specific optical system of interacting light intensities and phosphor materials.
The prior art for computational systems employing optical components all appears to rely upon electrical power, electrical components or both. See, for example, U.S. Pat. No. 5,784,309 issued Jul. 21, 1998. While U.S. Pat. No. 5,784,309 and others may employ a damping force in their process, no prior art was found which utilizes the second-order susceptibility effects (to include quenching) as an integral part of the mathematical computation and variables.
The present invention uniquely and separately teaches: the combination of multiple phosphors in not less than two first-order relaxation subsystems to perform mathematical operations; the utilization of the second-order effects (e.g., quenching) of phosphor to perform mathematical operations; the combining of the not less than two first-order relaxation subsystems with the second-order effects (e.g., quenching) of phosphor to perform mathematical operations; and the ability to perform any or all of the above teachings without the necessity of electrical power or components.
A significant potential benefit of an all-optical (non-electric) system is its application to isolated environments (e.g., space exploration) where a limited power supply must be considered in all planning and design activities.